Fractal Geometry Illustrated Left Atrial Appendage Morphology That Predicted Thrombosis and Stroke in Patients With Atrial Fibrillation

Q: What is the clinical evidence from this study?

Study design: Cohort. Population: Atrial Fibrillation (n=489). Intervention: Fractal dimension (FD) combined with CHA2DS2-VaSc score vs. CHA2DS2-VaSc score alone. Primary outcome: Diagnostic accuracy (Area Under the Curve) for LAA thrombosis in low- to moderate-risk patients (95% CI 0.733-0.963, p=0.009).

Chuxiang Lei; Qi Gao; Runjie Wei; Qijie Li; Xingli Liu; Lingmin Wu; Yan Yao; Hongguang Fan; Zhe Zheng

doi:10.3389/fcvm.2022.779528

May 10, 2022Frontiers in Cardiovascular MedicineOpen Access

Fractal Geometry Illustrated Left Atrial Appendage Morphology That Predicted Thrombosis and Stroke in Patients With Atrial Fibrillation

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Key result

Combining left atrial appendage fractal dimension with the CHA2DS2-VaSc score significantly improved diagnostic accuracy for predicting thrombosis compared to the CHA2DS2-VaSc score alone in low- to moderate-risk patients with atrial fibrillation (AUC 0.848 vs 0.696, p=0.009).

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Why the study?

This study aimed to correlate the morphological complexity of the left atrial appendage with thrombosis and stroke in patients with AF.

Does fractal dimension analysis of left atrial appendage morphology improve the prediction of thrombosis and stroke compared to CHA2DS2-VASc score alone in patients with atrial fibrillation?

Study Design

Type

Cohort (n=489)

Multicenter

No

Structured PICO

Does fractal dimension analysis of left atrial appendage morphology improve the prediction of thrombosis and stroke compared to CHA2DS2-VASc score alone in patients with atrial fibrillation?

P

Population

489 patients with atrial fibrillation (46 in a training cohort and 443 in a validation cohort) who underwent multidetector computed tomography of the left atrium to evaluate the association between left atrial appendage morphological complexity and thrombosis or stroke.

E

Exposure

Fractal dimension (FD) analysis of left atrial appendage (LAA) morphological complexity combined with CHA2DS2-VASc score

C

Comparator

CHA2DS2-VASc score alone

O

Outcome

LAA thrombosis and strokesurrogate

Main Result

Absolute Event Rate: 0.848% vs 0.696%

p-value: p=0.009

Fractal dimension analysis of LAA morphology combined with the CHA2DS2-VASc score significantly improves the prediction of LAA thrombosis and stroke in patients with atrial fibrillation.

Limitations

Relatively small sample size collected from a single center and retrospective nature might cause selection bias.
Diagnosis of LAA thrombus in the training cohort largely depended on TEE images rather than pathological or surgical examination.
Absence of anticoagulants in the treatment of included patients before CT or TEE could be a confounding factor.
The 3D reconstructed model cannot wholly reflect the internal shape of the patient's LAA because the contrast agent may not be completely adherent during scanning.

Implication

May enhance thrombosis prediction in low-moderate risk AF; leaves open need for prospective validation before clinical adoption.

Abstract

Background This study aims to correlate the morphological complexity of left atrial appendage (LAA) with thrombosis and stroke in patients with atrial fibrillation (AF). Methods The training cohort consisted of 46 patients with AF (age 55.8 ± 7.2 years, 73.9% men) who were referred for radiofrequency catheter ablation. An independent validation cohort consisting of 443 patients with AF was enrolled for further verification. All patients in the training cohort underwent both transesophageal echocardiography (TEE) and enhanced computed tomography (CT). Fractal dimension (FD) analysis was performed to evaluate the morphological complexity of LAAs quantitatively. Clinical and imaging manifestations, FD of LAAs, and diagnostic accuracy were investigated and compared between patients with AF in both training and validation cohorts. Results In the training cohort, LAAs ( n = 22) with thrombi had significantly higher FD than those without thrombi ( n = 24) h 0.44 ± 0.07 vs. 2.35 ± 0.11, p = 0.003). Receiver-operating characteristic (ROC) analysis suggested that the diagnostic accuracy of FD combined with a CHA 2 DS 2 -VaSc score was significantly higher than that of the CHA 2 DS 2 -VaSc score alone in low- to moderate-risk patients with AF (area under the curve 0.8479 vs. 0.6958, p = 0.009). The results were also validated in an independent external validation cohort and demonstrated that increased FD was associated with stroke. Hemodynamic analysis revealed that LAAs with thrombi and high FD were prone to blood stasis and lower blood flow rate. Conclusion LAA morphological complexity is closely associated with thrombosis and stroke in patients with paroxysmal AF. A new risk assessment system combining CHA 2 DS 2 -VaSc score and FD has a higher diagnostic accuracy in predicting LAA thrombosis.

Discussion

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Cite This Study

Lei et al. (2022) conducted a cohort in Atrial Fibrillation (n=489). Fractal dimension (FD) combined with CHA2DS2-VaSc score vs. CHA2DS2-VaSc score alone was evaluated on Diagnostic accuracy (Area Under the Curve) for LAA thrombosis in low- to moderate-risk patients (95% CI 0.733-0.963, p=0.009). Combining left atrial appendage fractal dimension with the CHA2DS2-VaSc score significantly improved diagnostic accuracy for predicting thrombosis compared to the CHA2DS2-VaSc score alone in low- to moderate-risk patients with atrial fibrillation (AUC 0.848 vs 0.696, p=0.009).

synapsesocial.com/papers/6a221af1e8ef4064f24ebe0a https://doi.org/10.3389/fcvm.2022.779528